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Dr. Mani Shrestha
Bio-Inspired Digital Sensing Lab (BIDs-Lab), School of Media and Communication, RMIT University, Melbourne, VIC 3001, Australia

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0 Agroecology
0 Community Ecology
0 Urban Ecology
0 Insect vision
0 Macroecology

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Journal article
Published: 15 August 2021 in Journal of Experimental Biology
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The majority of angiosperms require animal pollination for reproduction, and insects are the dominant group of animal pollinators. Bees are considered one of the most important and abundant insect pollinators. Research into bee behaviour and foraging decisions has typically centred on managed eusocial bee species, including Apis mellifera and Bombus terrestris. Non-eusocial bees are understudied with respect to foraging strategies and decision making, such as flower preferences. Understanding whether there are fundamental foraging strategies and preferences that are features of insect groups can provide key insights into the evolution of flower–pollinator co-evolution. In the current study, Lasioglossum (Chilalictus) lanarium and Lasioglossum (Parasphecodes) sp., two native Australian generalist halictid bees, were tested for flower shape preferences between native insect-pollinated and bird-pollinated flowers. Each bee was presented with achromatic images of either insect-pollinated or bird-pollinated flowers in a circular arena. Both native bee species demonstrated a significant preference for images of insect-pollinated flowers. These preferences are similar to those found in A. mellifera, suggesting that flower shape preference may be a deep-rooted evolutionary occurrence within bees. With growing interest in the sensory capabilities of non-eusocial bees as alternative pollinators, the current study also provides a valuable framework for further behavioural testing of such species.

ACS Style

Scarlett R. Howard; Kit Prendergast; Matthew R. E. Symonds; Mani Shrestha; Adrian G. Dyer. Spontaneous choices for insect-pollinated flower shapes by wild non-eusocial halictid bees. Journal of Experimental Biology 2021, 224, 1 .

AMA Style

Scarlett R. Howard, Kit Prendergast, Matthew R. E. Symonds, Mani Shrestha, Adrian G. Dyer. Spontaneous choices for insect-pollinated flower shapes by wild non-eusocial halictid bees. Journal of Experimental Biology. 2021; 224 (16):1.

Chicago/Turabian Style

Scarlett R. Howard; Kit Prendergast; Matthew R. E. Symonds; Mani Shrestha; Adrian G. Dyer. 2021. "Spontaneous choices for insect-pollinated flower shapes by wild non-eusocial halictid bees." Journal of Experimental Biology 224, no. 16: 1.

Journal article
Published: 30 March 2021 in Diversity
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There is increasing interest in developing urban design principles that incorporate good ecological management. Research on understanding the distribution and role of beneficial pollinating insects, in particular, is changing our view of the ecological value of cities. With the rapid expansion of the built environment comes a need to understand how insects may be affected in extensive urban areas. We therefore investigated insect pollinator capture rates in a rapidly growing and densely urbanized city (Melbourne, Australia). We identified a remnant native habitat contained within the expansive urban boundary, and established study sites at two nearby populated urban areas. We employed standard pan trap sampling techniques to passively sample insect orders in the different environments. Our results show that, even though the types of taxonomic groups of insects captured are comparable between locations, important pollinators like bees and hoverflies were more frequently captured in the remnant native habitat. By contrast, beetles (Coleoptera) and butterflies/moths (Lepidoptera) were more frequently observed in the urban residential regions. Our results suggest that the maintenance of native habitat zones within cities is likely to be valuable for the conservation of bees and the ecosystem services they provide.

ACS Style

Mani Shrestha; Jair Garcia; Freya Thomas; Scarlett Howard; Justin Chua; Thomas Tscheulin; Alan Dorin; Anders Nielsen; Adrian Dyer. Insects in the City: Does Remnant Native Habitat Influence Insect Order Distributions? Diversity 2021, 13, 148 .

AMA Style

Mani Shrestha, Jair Garcia, Freya Thomas, Scarlett Howard, Justin Chua, Thomas Tscheulin, Alan Dorin, Anders Nielsen, Adrian Dyer. Insects in the City: Does Remnant Native Habitat Influence Insect Order Distributions? Diversity. 2021; 13 (4):148.

Chicago/Turabian Style

Mani Shrestha; Jair Garcia; Freya Thomas; Scarlett Howard; Justin Chua; Thomas Tscheulin; Alan Dorin; Anders Nielsen; Adrian Dyer. 2021. "Insects in the City: Does Remnant Native Habitat Influence Insect Order Distributions?" Diversity 13, no. 4: 148.

The scientific naturalist
Published: 12 March 2021 in Ecology
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The genus Roscoea, a Himalayan endemic and only alpine member of the predominately tropical family Zingiberaceae, is well‐known for possessing elaborate floral traits commonly associated with biotic pollination, and particularly with long‐tongued fly pollination. These traits include showy, easily detectable flowers with wide labellum serving as a landing platform for floral visitors, absence of discernible fragrance, presence of nectar as a reward, elongated reproductive organs situated away from the nectar source, and long corolla tube that is compatible with the tongue length of long‐tongued insects (Goldblatt and Manning 2000, Cowley 2007).

ACS Style

Babu Ram Paudel; Mani Shrestha; Martin Burd; Qing‐Jun Li. Dual mechanisms of autonomous selfing in Roscoea nepalensis (Zingiberaceae). Ecology 2021, 102, e03337 .

AMA Style

Babu Ram Paudel, Mani Shrestha, Martin Burd, Qing‐Jun Li. Dual mechanisms of autonomous selfing in Roscoea nepalensis (Zingiberaceae). Ecology. 2021; 102 (7):e03337.

Chicago/Turabian Style

Babu Ram Paudel; Mani Shrestha; Martin Burd; Qing‐Jun Li. 2021. "Dual mechanisms of autonomous selfing in Roscoea nepalensis (Zingiberaceae)." Ecology 102, no. 7: e03337.

Review
Published: 15 January 2021 in Frontiers in Plant Science
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Blue is a favored color of many humans. While blue skies and oceans are a common visual experience, this color is less frequently observed in flowers. We first review how blue has been important in human culture, and thus how our perception of blue has likely influenced the way of scientifically evaluating signals produced in nature, including approaches as disparate as Goethe’s Farbenlehre, Linneaus’ plant taxonomy, and current studies of plant-pollinator networks. We discuss the fact that most animals, however, have different vision to humans; for example, bee pollinators have trichromatic vision based on UV-, Blue-, and Green-sensitive photoreceptors with innate preferences for predominantly short-wavelength reflecting colors, including what we perceive as blue. The subsequent evolution of blue flowers may be driven by increased competition for pollinators, both because of a harsher environment (as at high altitude) or from high diversity and density of flowering plants (as in nutrient-rich meadows). The adaptive value of blue flowers should also be reinforced by nutrient richness or other factors, abiotic and biotic, that may reduce extra costs of blue-pigments synthesis. We thus provide new perspectives emphasizing that, while humans view blue as a less frequently evolved color in nature, to understand signaling, it is essential to employ models of biologically relevant observers. By doing so, we conclude that short wavelength reflecting blue flowers are indeed frequent in nature when considering the color vision and preferences of bees.

ACS Style

Adrian G. Dyer; Anke Jentsch; Martin Burd; Jair E. Garcia; Justyna Giejsztowt; Maria G. G. Camargo; Even Tjørve; Kathleen M. C. Tjørve; Peter White; Mani Shrestha. Fragmentary Blue: Resolving the Rarity Paradox in Flower Colors. Frontiers in Plant Science 2021, 11, 1 .

AMA Style

Adrian G. Dyer, Anke Jentsch, Martin Burd, Jair E. Garcia, Justyna Giejsztowt, Maria G. G. Camargo, Even Tjørve, Kathleen M. C. Tjørve, Peter White, Mani Shrestha. Fragmentary Blue: Resolving the Rarity Paradox in Flower Colors. Frontiers in Plant Science. 2021; 11 ():1.

Chicago/Turabian Style

Adrian G. Dyer; Anke Jentsch; Martin Burd; Jair E. Garcia; Justyna Giejsztowt; Maria G. G. Camargo; Even Tjørve; Kathleen M. C. Tjørve; Peter White; Mani Shrestha. 2021. "Fragmentary Blue: Resolving the Rarity Paradox in Flower Colors." Frontiers in Plant Science 11, no. : 1.

Original research article
Published: 17 December 2020 in Frontiers in Plant Science
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Pollinators with different vision are a key driver of flower coloration. Islands provide important insights into evolutionary processes, and previous work suggests islands may have restricted flower colors. Due to both species richness with high endemism in tropical–subtropical environments, and potentially changing pollinator distributions with altitude, we evaluated flower color diversity across the mountainous island of Taiwan in a comparative framework to understand the cause of color diversity. We sampled flower color signaling on the tropical–subtropical island of Taiwan considering altitudes from sea level to 3300 m to inform how over-dispersion, random processes or clustering may influence flower signaling. We employed a model of bee color space to plot loci from 727 species to enable direct comparisons to data sets from continental studies representing Northern and Southern Hemispheres, and also a continental mountain region. We observed that flower color diversity was similar to flowers that exist in mainland continental studies, and also showed evidence that flowers predominantly had evolved color signals that closely matched bee color preferences. At high altitudes floras tend to be phylogenetically clustered rather than over-dispersed, and their floral colors exhibited weak phylogenetic signal which is consistent with character displacement that facilitated the co-existence of related species. Overall flower color signaling on a tropical–subtropical island is mainly influenced by color preferences of key bee pollinators, a pattern consistent with continental studies.

ACS Style

King-Chun Tai; Mani Shrestha; Adrian G. Dyer; En-Cheng Yang; Chun-Neng Wang. Floral Color Diversity: How Are Signals Shaped by Elevational Gradient on the Tropical–Subtropical Mountainous Island of Taiwan? Frontiers in Plant Science 2020, 11, 1 .

AMA Style

King-Chun Tai, Mani Shrestha, Adrian G. Dyer, En-Cheng Yang, Chun-Neng Wang. Floral Color Diversity: How Are Signals Shaped by Elevational Gradient on the Tropical–Subtropical Mountainous Island of Taiwan? Frontiers in Plant Science. 2020; 11 ():1.

Chicago/Turabian Style

King-Chun Tai; Mani Shrestha; Adrian G. Dyer; En-Cheng Yang; Chun-Neng Wang. 2020. "Floral Color Diversity: How Are Signals Shaped by Elevational Gradient on the Tropical–Subtropical Mountainous Island of Taiwan?" Frontiers in Plant Science 11, no. : 1.

Original paper
Published: 19 November 2020 in Theoretical Ecology
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Heterospecific pollen transfer by insect pollinators has the potential to drive inter-species competition between flowering plants. This phenomenon may newly arise in a region if insect pollinator or flowering plant populations change. An agent-based simulation is presented to assess the potential impact of heterospecific pollen transfer by insects on two co-flowering plant species within an environment consisting of a shared central region and species-specific refugia. Where heterospecific pollen asymmetrically suppressed the reproduction of one competitor, the pollen recipient was rapidly ousted from shared regions. If pollinators made deep, repeated, forays into and out of plant refugia, the clogged species was even unseated from its own refugium. When heterospecific pollen symmetrically suppressed plant reproduction, the same effects were observed, but with one or the other species excluded at random by the pollen clogging mediated interaction. We conclude that both symmetrical and asymmetrical heterospecific pollen transfer may be important elements of inter-species dynamics. In particular, our simulation shows pollen and pollinator visits lost to heterospecific flowers may not always be wasted from the producer’s standpoint. Instead, heterospecific pollen delivery may convey a competitive advantage even when the recipient has a refuge safe from direct invasion. This is possible because the pollen producer may use pollinators to clog a competitor’s stigmas in a refugium without entering into competition there for space, nutrients, light, pollinators, or other resources. Consequently, the evolution of plant signals to promote pollinator constancy may not be the only effective strategy in inter-species competition.

ACS Style

Alan Dorin; Tim Taylor; Martin Burd; Julian Garcia; Mani Shrestha; Adrian G. Dyer. Competition and pollen wars: simulations reveal the dynamics of competition mediated through heterospecific pollen transfer by non-flower constant insects. Theoretical Ecology 2020, 1 -12.

AMA Style

Alan Dorin, Tim Taylor, Martin Burd, Julian Garcia, Mani Shrestha, Adrian G. Dyer. Competition and pollen wars: simulations reveal the dynamics of competition mediated through heterospecific pollen transfer by non-flower constant insects. Theoretical Ecology. 2020; ():1-12.

Chicago/Turabian Style

Alan Dorin; Tim Taylor; Martin Burd; Julian Garcia; Mani Shrestha; Adrian G. Dyer. 2020. "Competition and pollen wars: simulations reveal the dynamics of competition mediated through heterospecific pollen transfer by non-flower constant insects." Theoretical Ecology , no. : 1-12.

Research article
Published: 11 June 2020 in PLOS ONE
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Colour is an important signal that flowering plants use to attract insect pollinators like bees. Previous research in Germany has shown that nectar volume is higher for flower colours that are innately preferred by European bees, suggesting an important link between colour signals, bee preferences and floral rewards. In Australia, flower colour signals have evolved in parallel to the Northern hemisphere to enable easy discrimination and detection by the phylogenetically ancient trichromatic visual system of bees, and native Australian bees also possess similar innate colour preferences to European bees. We measured 59 spectral signatures from flowers present at two preserved native habitats in South Eastern Australia and tested whether there were any significant differences in the frequency of flowers presenting higher nectar rewards depending upon the colour category of the flower signals, as perceived by bees. We also tested if there was a significant correlation between chromatic contrast and the frequency of flowers presenting higher nectar rewards. For the entire sample, and for subsets excluding species in the Asteraceae and Orchidaceae, we found no significant difference among colour categories in the frequency of high nectar reward. This suggests that whilst such relationships between flower colour signals and nectar volume rewards have been observed at a field site in Germany, the effect is likely to be specific at a community level rather than a broad general principle that has resulted in the common signalling of bee flower colours around the world.

ACS Style

Mani Shrestha; Jair E. Garcia; Martin Burd; Adrian G. Dyer. Australian native flower colours: Does nectar reward drive bee pollinator flower preferences? PLOS ONE 2020, 15, e0226469 .

AMA Style

Mani Shrestha, Jair E. Garcia, Martin Burd, Adrian G. Dyer. Australian native flower colours: Does nectar reward drive bee pollinator flower preferences? PLOS ONE. 2020; 15 (6):e0226469.

Chicago/Turabian Style

Mani Shrestha; Jair E. Garcia; Martin Burd; Adrian G. Dyer. 2020. "Australian native flower colours: Does nectar reward drive bee pollinator flower preferences?" PLOS ONE 15, no. 6: e0226469.

Review article
Published: 17 March 2020 in Plant Biology
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About one‐third of orchid species are thought to offer no floral reward and therefore to attract pollinators through deception. Statements of this idea are common in the botanical literature, but the empirical basis of the estimate is rarely mentioned. We traced citation pathways for the one‐third estimate in a sample of the literature and found that the paths lead to empirical foundations that are surprisingly narrow. Moreover, recent measurements have detected minute quantities of sugar available to insect visitors in some orchids thought to be rewardless, raising the possibility of a pollination strategy that is largely deceitful but different to absolute rewardlessness. The orchids are a well studied group and there is no doubt that rewardlessness is common in the family. However, greater empirical effort is needed to verify rewardlessness in orchids and to explore geographic and environmental variation in the proportion of rewardless species.

ACS Style

Mani Shrestha; Adrian G. Dyer; Alan Dorin; Zong‐Xin Ren; Martin Burd. Rewardlessness in orchids: how frequent and how rewardless? Plant Biology 2020, 22, 555 -561.

AMA Style

Mani Shrestha, Adrian G. Dyer, Alan Dorin, Zong‐Xin Ren, Martin Burd. Rewardlessness in orchids: how frequent and how rewardless? Plant Biology. 2020; 22 (4):555-561.

Chicago/Turabian Style

Mani Shrestha; Adrian G. Dyer; Alan Dorin; Zong‐Xin Ren; Martin Burd. 2020. "Rewardlessness in orchids: how frequent and how rewardless?" Plant Biology 22, no. 4: 555-561.

Micro article
Published: 21 February 2020 in MethodsX
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A spectral reflectance curve for a coloured surface can be constructed from a set of radiation reflectance value measurements made across the spectrum at discrete wavelengths. The curve gives an indication of the pattern of light entering the eye of an organism viewing an illuminated object. Marker points represent the positions along a reflectance curve at which sharp transitions in reflectance occur, these being potentially important to visual perception, for instance by insects discriminating between two flowers, each of a different colour. Consequently, methods of marker point analysis have been applied in several studies evaluating flower colours. These studies have sometimes required researchers to place marker points on reflectance curves by eye, or they have used algorithms written as unreleased software. To automate the process systematically and provide open access, we implemented special-purpose software in C++. Below we provide a summary of the approach adopted in our implementation and made available online in a port to TypeScript. The main benefits of our method are summarized as being:

ACS Style

Alan Dorin; Mani Shrestha; Matthieu Herrmann; Martin Burd; Adrian G. Dyer. Automated calculation of spectral-reflectance marker-points to enable analysis of plant colour-signalling to pollinators. MethodsX 2020, 7, 100827 .

AMA Style

Alan Dorin, Mani Shrestha, Matthieu Herrmann, Martin Burd, Adrian G. Dyer. Automated calculation of spectral-reflectance marker-points to enable analysis of plant colour-signalling to pollinators. MethodsX. 2020; 7 ():100827.

Chicago/Turabian Style

Alan Dorin; Mani Shrestha; Matthieu Herrmann; Martin Burd; Adrian G. Dyer. 2020. "Automated calculation of spectral-reflectance marker-points to enable analysis of plant colour-signalling to pollinators." MethodsX 7, no. : 100827.

Research article
Published: 01 January 2020 in International Journal of Wildland Fire
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Alpine vegetation of the Himalaya is used as food, medicine or fodder, and is commonly managed with fire by agropastoralists. Prescribed fire can have positive effects on rangeland biodiversity, but studies evaluating its effects in alpine shrublands are scarce. Our objective was to examine the effects of anthropogenic fire on biophysical characteristics, species richness, abundance and composition in an alpine shrubland with socioeconomic value to local peoples in Langtang National Park in central Nepal. We surveyed biophysical variables, vascular plant species richness and composition along three transects at ascending elevations, and conducted interviews with local people and park officials on the use of fire in the region. We found 69 species of vascular plants in 89 plots; species richness was greater in burned plots and with increasing elevation, with 13 species unique to burned plots. We identified 14 indicator species in both burned and unburned plots; eight of them were Himalayan endemics. In burned plots, the indicator species were predominantly grasses and perennial forbs with ethnobotanical uses. This is the first detailed study on alpine shrubland anthropogenic fire in the Nepalese Himalaya. Burning may, at least temporarily, replace woody with more palatable herbaceous species, and weaken the elevational gradient of the shrubland.

ACS Style

Asha Paudel; Scott H. Markwith; Katie Konchar; Mani Shrestha; Suresh K. Ghimire. Anthropogenic fire, vegetation structure and ethnobotanical uses in an alpine shrubland of Nepal’s Himalaya. International Journal of Wildland Fire 2020, 29, 201 .

AMA Style

Asha Paudel, Scott H. Markwith, Katie Konchar, Mani Shrestha, Suresh K. Ghimire. Anthropogenic fire, vegetation structure and ethnobotanical uses in an alpine shrubland of Nepal’s Himalaya. International Journal of Wildland Fire. 2020; 29 (3):201.

Chicago/Turabian Style

Asha Paudel; Scott H. Markwith; Katie Konchar; Mani Shrestha; Suresh K. Ghimire. 2020. "Anthropogenic fire, vegetation structure and ethnobotanical uses in an alpine shrubland of Nepal’s Himalaya." International Journal of Wildland Fire 29, no. 3: 201.

Original paper
Published: 29 May 2019 in Journal of Comparative Physiology A
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Innate colour preferences promote the capacity of pollinators to find flowers, although currently there is a paucity of data on how preferences apply to real flowers. The Australian sugarbag bee (Tetragonula carbonaria Sm.) has innate preferences for colours, including UV-absorbing white. Sugarbag bees are pollinators of the terrestrial orchid Caladenia carnea R.Br., which has both white and pink morphs. In laboratory conditions, we tested flower-naïve bees with the white and pink flower morphs revealing a significant preference for the white morph, consistent with experiments using artificial stimuli. In experiments to understand how bees may select food-deceptive orchids following habituation to a particular colour morph, we observed a significant increase in choices towards novel white flowers. We also observed that the presence of a UV-reflecting dorsal sepal signal significantly increased bee choices compared to flowers that had the UV signal blocked. Our findings demonstrate that innate preference testing of insect pollinators with artificial stimuli is replicated in a biologically significant scenario with flowers. The findings also underscore how food-deceptive orchids can receive sufficient pollinator visits to ensure pollination by having different morphs that draw on the innate preferences of bees and their ability to make decisions in a complex ecological setting.

ACS Style

Adrian G. Dyer; Skye Boyd-Gerny; Mani Shrestha; Jair E. Garcia; Casper J. Van Der Kooi; Bob B. M. Wong. Colour preferences of Tetragonula carbonaria Sm. stingless bees for colour morphs of the Australian native orchid Caladenia carnea. Journal of Comparative Physiology A 2019, 205, 347 -361.

AMA Style

Adrian G. Dyer, Skye Boyd-Gerny, Mani Shrestha, Jair E. Garcia, Casper J. Van Der Kooi, Bob B. M. Wong. Colour preferences of Tetragonula carbonaria Sm. stingless bees for colour morphs of the Australian native orchid Caladenia carnea. Journal of Comparative Physiology A. 2019; 205 (3):347-361.

Chicago/Turabian Style

Adrian G. Dyer; Skye Boyd-Gerny; Mani Shrestha; Jair E. Garcia; Casper J. Van Der Kooi; Bob B. M. Wong. 2019. "Colour preferences of Tetragonula carbonaria Sm. stingless bees for colour morphs of the Australian native orchid Caladenia carnea." Journal of Comparative Physiology A 205, no. 3: 347-361.

Journal article
Published: 22 April 2019 in Annals of Botany
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Background and Aims Pollinator-mediated interactions between plant species may affect the composition of angiosperm communities. Floral colour signals should play a role in these interactions, but the role will arise from the visual perceptions and behavioural responses of multiple pollinators. Recent advances in the visual sciences can be used to inform our understanding of these perceptions and responses. We outline the application of appropriate visual principles to the analysis of the annual cycle of floral colour structure in two Australian herbaceous communities. Methods We used spectrographic measurements of petal reflectance to determine the location of flowers in a model of hymenopteran colour vision. These representations of colour perception were then translated to a behaviourally relevant metric of colour differences using empirically calibrated colour discrimination functions for four hymenopteran species. We then analysed the pattern of colour similarity in terms of this metric in samples of co-flowering plants over the course of a year. We used the same method to analyse the annual pattern of phylogenetic relatedness of co-flowering plants in order to compare colour structure and phylogenetic structure. Key Results Co-flowering communities at any given date seldom had colour assemblages significantly different from random. Non-random structure, both dispersion and clustering, occurred occasionally, but depended on which bee observer is considered. The degree of colour similarity was unrelated to phylogenetic similarity within a co-flowering community. Conclusions Perceived floral colour structure varied with the sensory capabilities of the observer. The lack of colour structure at most sample dates, particularly the rarity of strong dispersion, suggests that plants do not use chromatic signals primarily to enable bees to discriminate between co-flowering species. It is more likely that colours make plants detectable in a complex landscape.

ACS Style

Mani Shrestha; Adrian G Dyer; Jair E Garcia; Martin Burd. Floral colour structure in two Australian herbaceous communities: it depends on who is looking. Annals of Botany 2019, 124, 221 -232.

AMA Style

Mani Shrestha, Adrian G Dyer, Jair E Garcia, Martin Burd. Floral colour structure in two Australian herbaceous communities: it depends on who is looking. Annals of Botany. 2019; 124 (2):221-232.

Chicago/Turabian Style

Mani Shrestha; Adrian G Dyer; Jair E Garcia; Martin Burd. 2019. "Floral colour structure in two Australian herbaceous communities: it depends on who is looking." Annals of Botany 124, no. 2: 221-232.

Commentary
Published: 20 March 2019 in New Phytologist
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This article is a Commentary on Camargo et al., 222: 1112–1122.

ACS Style

Adrian G. Dyer; Mani Shrestha. Assessment of floral colour signals at a community through the eyes of the birds and bees. New Phytologist 2019, 222, 648 -650.

AMA Style

Adrian G. Dyer, Mani Shrestha. Assessment of floral colour signals at a community through the eyes of the birds and bees. New Phytologist. 2019; 222 (2):648-650.

Chicago/Turabian Style

Adrian G. Dyer; Mani Shrestha. 2019. "Assessment of floral colour signals at a community through the eyes of the birds and bees." New Phytologist 222, no. 2: 648-650.

Journal article
Published: 01 February 2019 in Insects
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To monitor and quantify the changes in pollinator communities over time, it is important to have robust survey techniques of insect populations. Pan traps allow for the assessment of the relative insect abundance in an environment and have been promoted by the Food and Agricultural Organization (FAO) as an efficient data collection methodology. It has been proposed that fluorescent pan traps are particularly useful, as it has been suggested that they capture high numbers of insects in an unbiased fashion. We use a simultaneous presentation of fluorescent and non-fluorescent pan trap colours to assess how flower-visiting insects of different orders respond to visual stimuli and reveal a significant interaction between trap fluorescence and captured insect type. In particular, Coleoptera (beetles) and Lepidoptera (butterflies and moths) were captured significantly more frequently by fluorescent traps, whilst Dipterans (flies) were captured significantly less frequently by this type of pan trap. Hymenopterans (bees and wasps) showed no significant difference in their preference for fluorescent or non-fluorescent traps. Our results reveal that the use of fluorescent pan traps may differently bias insect capture rates when compared to the typical experience of colour flower-visiting insects in natural environments. Correction factors may, therefore, be required for interpreting insect pan trap data collected with different methodologies.

ACS Style

Mani Shrestha; Jair E. Garcia; Justin H. J. Chua; Scarlett R. Howard; Thomas Tscheulin; Alan Dorin; Anders Nielsen; Adrian G. Dyer. Fluorescent Pan Traps Affect the Capture Rate of Insect Orders in Different Ways. Insects 2019, 10, 40 .

AMA Style

Mani Shrestha, Jair E. Garcia, Justin H. J. Chua, Scarlett R. Howard, Thomas Tscheulin, Alan Dorin, Anders Nielsen, Adrian G. Dyer. Fluorescent Pan Traps Affect the Capture Rate of Insect Orders in Different Ways. Insects. 2019; 10 (2):40.

Chicago/Turabian Style

Mani Shrestha; Jair E. Garcia; Justin H. J. Chua; Scarlett R. Howard; Thomas Tscheulin; Alan Dorin; Anders Nielsen; Adrian G. Dyer. 2019. "Fluorescent Pan Traps Affect the Capture Rate of Insect Orders in Different Ways." Insects 10, no. 2: 40.

Research paper
Published: 25 January 2019 in Plant Biology
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Orchids are a classic angiosperm model for understanding biotic pollination. We studied orchid species within two species‐rich herbaceous communities that are known to have either hymenopteran or dipteran insects as the dominant pollinators, in order to understand how flower colour relates to pollinator visual systems. We analysed features of the floral reflectance spectra that are significant to pollinator visual systems and used models of dipteran and hymenopteran colour vision to characterise the chromatic signals used by fly‐pollinated and bee‐pollinated orchid species. In contrast to bee‐pollinated flowers, fly‐pollinated flowers had distinctive points of rapid reflectance change at long wavelengths and a complete absence of such spectral features at short wavelengths. Fly‐pollinated flowers also had significantly more restricted loci than bee‐pollinated flowers in colour space models of fly and bee vision alike. Globally, bee‐pollinated flowers are known to have distinctive, consistent colour signals. Our findings of different signals for fly pollination is consistent with pollinator‐mediated selection on orchid species that results from the distinctive features of fly visual systems.

ACS Style

M. Shrestha; M. Burd; J. E. Garcia; A. Dorin; A. G. Dyer. Colour evolution within orchids depends on whether the pollinator is a bee or a fly. Plant Biology 2019, 21, 745 -752.

AMA Style

M. Shrestha, M. Burd, J. E. Garcia, A. Dorin, A. G. Dyer. Colour evolution within orchids depends on whether the pollinator is a bee or a fly. Plant Biology. 2019; 21 (4):745-752.

Chicago/Turabian Style

M. Shrestha; M. Burd; J. E. Garcia; A. Dorin; A. G. Dyer. 2019. "Colour evolution within orchids depends on whether the pollinator is a bee or a fly." Plant Biology 21, no. 4: 745-752.

Journal article
Published: 13 December 2018 in Current Zoology
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Plant-pollinator interactions have a fundamental influence on flower evolution. Flower color signals are frequently tuned to the visual capabilities of important pollinators such as either bees or birds, but far less is known about whether flower shape influences the choices of pollinators. We tested European honeybee Apis mellifera preferences using novel achromatic (gray-scale) images of 12 insect-pollinated and 12 bird-pollinated native Australian flowers in Germany; thus, avoiding influences of color, odor, or prior experience. Independent bees were tested with a number of parameterized images specifically designed to assess preferences for size, shape, brightness, or the number of flower-like shapes present in an image. We show that honeybees have a preference for visiting images of insect-pollinated flowers and such a preference is most-likely mediated by holistic information rather than by individual image parameters. Our results indicate angiosperms have evolved flower shapes which influence the choice behavior of important pollinators, and thus suggest spatial achromatic flower properties are an important part of visual signaling for plant-pollinator interactions.

ACS Style

Scarlett R Howard; Mani Shrestha; Juergen Schramme; Jair E Garcia; Aurore Avarguès-Weber; Andrew D Greentree; Adrian G Dyer. Honeybees prefer novel insect-pollinated flower shapes over bird-pollinated flower shapes. Current Zoology 2018, 65, 457 -465.

AMA Style

Scarlett R Howard, Mani Shrestha, Juergen Schramme, Jair E Garcia, Aurore Avarguès-Weber, Andrew D Greentree, Adrian G Dyer. Honeybees prefer novel insect-pollinated flower shapes over bird-pollinated flower shapes. Current Zoology. 2018; 65 (4):457-465.

Chicago/Turabian Style

Scarlett R Howard; Mani Shrestha; Juergen Schramme; Jair E Garcia; Aurore Avarguès-Weber; Andrew D Greentree; Adrian G Dyer. 2018. "Honeybees prefer novel insect-pollinated flower shapes over bird-pollinated flower shapes." Current Zoology 65, no. 4: 457-465.

Journal article
Published: 13 December 2018 in Current Zoology
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Angle dependent colors, such as iridescence, are produced by structures present on flower petals changing their visual appearance. These colors have been proposed to act as signals for plant-insect communication. However, there is a paucity of behavioral data to allow for interpretations of how to classify these colors either as a signal or a cue when considering the natural conditions under which pollination occurs. We sampled flowers from 6 plant species across various viewpoints looking for changes in the visual appearance of the petals. Spectral characteristics were measured with different instruments to simulate both the spectral and spatial characteristics of honeybee's vision. We show the presence of color patches produced by angle dependent effects on the petals and the calyx of various species; however, the appearance of the angle dependent color patches significantly varies with viewpoint and would only be resolved by the insect eye at close distances. Behavior experiments with honeybees revealed that pollinators did not use angle dependent colors to drive behavior when presented with novel flower presentations. Results show that angle dependent colors do not comply with the requirements of a signal for plant-pollinator communication since the information transmitted by these colors would be unreliable for potential, free-flying pollination vectors. We thus classify angle dependent colors produced by micro- and ultra-structures as being a cue (a feature which has not evolved for communication), and observe no evidence supporting claims of these angle dependent colors having evolved as visual signal.

ACS Style

Jair E Garcia; Mani Shrestha; Scarlett R Howard; Phred Petersen; Adrian G Dyer. Signal or cue: the role of structural colors in flower pollination. Current Zoology 2018, 65, 467 -481.

AMA Style

Jair E Garcia, Mani Shrestha, Scarlett R Howard, Phred Petersen, Adrian G Dyer. Signal or cue: the role of structural colors in flower pollination. Current Zoology. 2018; 65 (4):467-481.

Chicago/Turabian Style

Jair E Garcia; Mani Shrestha; Scarlett R Howard; Phred Petersen; Adrian G Dyer. 2018. "Signal or cue: the role of structural colors in flower pollination." Current Zoology 65, no. 4: 467-481.

Journal article
Published: 01 October 2018 in Behavioral Ecology
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Color discrimination thresholds proposed by receptor-noise type models are frequently used in animal vision studies to predict a precise limit on the capacity of an animal to discriminate between stimuli. Honeybees and bumblebees are 2 closely related hymenopteran species for which precise data on photoreceptor sensitivities and receptor noise exist, enabling accurate testing on how their vision conforms to model predictions. Color vision has been proved in these species, and they are known to predominantly visit flowers using visual signals to collect nutrition. Surprisingly, however, the natural variability of flower signals has been rarely considered, and recent work also suggests bees may tune color vision through experience. We initially measured the spectral variability of flowers from 2 species: Goodenia ovata and Rosemarinus officinalis where free-flying honeybees were observed constantly foraging from conspecific flowers. We empirically determined honeybee color discrimination thresholds for color stimuli considering either absolute- or differential-conditioning discrimination functions. Secondly, we analyzed greenhouse grown wild-type Antirrhinum majus flower petal spectra as well as spectra from mixta and nivea strains of this species, and empirically determined bumblebee color discrimination considering conditioning experience. In all measured cases, within-flower type spectral variability exceeded a 1.0 Receptor Noise threshold, often by several units. Observed behavioral color discrimination functions considering the respective conditioning procedures closely matched the range of signal variability for both honeybees and bumblebees, showing that color vision in bees cannot be described by a single fixed value, and plasticity is a key component of bee foraging behavior in natural environments.

ACS Style

Jair E Garcia; Mani Shrestha; Adrian G Dyer. Flower signal variability overwhelms receptor-noise and requires plastic color learning in bees. Behavioral Ecology 2018, 1 .

AMA Style

Jair E Garcia, Mani Shrestha, Adrian G Dyer. Flower signal variability overwhelms receptor-noise and requires plastic color learning in bees. Behavioral Ecology. 2018; ():1.

Chicago/Turabian Style

Jair E Garcia; Mani Shrestha; Adrian G Dyer. 2018. "Flower signal variability overwhelms receptor-noise and requires plastic color learning in bees." Behavioral Ecology , no. : 1.

Research article
Published: 01 August 2018 in PLOS ONE
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Climate change has the potential to enhance or disrupt biological systems, but currently, little is known about how organism plasticity may facilitate adaptation to localised climate variation. The bee-flower relationship is an exemplar signal-receiver system that may provide important insights into the complexity of ecological interactions in situations like this. For example, several studies on bee temperature preferences show that bees prefer to collect warm nectar from flowers at low ambient temperatures, but switch their preferences to cooler flowers at ambient temperatures above about 30° C. We used temperature sensor thermal probes to measure the temperature of outdoor flowers of 30 plant species in the Southern regions of the Australian mainland, to understand how different species could modulate petal temperature in response to changes in ambient temperature and, potentially, influence the decision-making of bees in the flowering plant’s favour. We found that flower petal temperatures respond in different ways to changing ambient temperature: linearly increasing or decreasing relative to the ambient temperature, dynamically changing in a non-linear manner, or varying their temperature along with the ambient conditions. For example, our investigation of the difference between ambient temperature and petal temperature (ΔT), and ambient temperature, revealed a non-linear relationship for Erysimum linifolium and Polygala grandiflora that seems suited to bee temperature preferences. The temperature profiles of species like Hibertia vestita and H. obtusifolia appear to indicate that they do not have a cooling mechanism. These species may therefore be less attractive to bee pollinators in changing climatic conditions with ambient temperatures increasingly above 30° C. This may be to the species’ detriment when insect-pollinator mediated selection is considered. However, we found no evidence that flower visual characteristics used by bees to identify flowers at close range, such as colour or shape, were straightforward modulators of floral temperature. We could not identify any clear link to phylogenetic history and temperature modulation either. Mapping our test flower distribution on the Australian continent however, indicates a potential clustering that suggests different flower responses may constitute adaptations to local conditions. Our study proposes a framework for modelling the potential effects of climate change and floral temperature on flower pollination dynamics at local and global scales.

ACS Style

Mani Shrestha; Jair E. Garcia; Zoë Bukovac; Alan Dorin; Adrian G. Dyer. Pollination in a new climate: Assessing the potential influence of flower temperature variation on insect pollinator behaviour. PLOS ONE 2018, 13, e0200549 .

AMA Style

Mani Shrestha, Jair E. Garcia, Zoë Bukovac, Alan Dorin, Adrian G. Dyer. Pollination in a new climate: Assessing the potential influence of flower temperature variation on insect pollinator behaviour. PLOS ONE. 2018; 13 (8):e0200549.

Chicago/Turabian Style

Mani Shrestha; Jair E. Garcia; Zoë Bukovac; Alan Dorin; Adrian G. Dyer. 2018. "Pollination in a new climate: Assessing the potential influence of flower temperature variation on insect pollinator behaviour." PLOS ONE 13, no. 8: e0200549.

Original article
Published: 10 July 2018 in Evolution
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Multiple barriers may contribute to reproductive isolation between closely related species. Understanding the relative strength of these barriers can illuminate the ecological factors that currently maintain species integrity and how these factors originally promoted speciation. Two Himalayan alpine gingers, Roscoea purpurea and R. tumjensis, occur sympatrically in central Nepal and have such similar morphology that it is not clear whether or how they maintain a distinct identity. Our quantitative measurements of the components of reproductive isolation show that they are, in fact, completely isolated by a combination of phenological displacement of flowering, earlier for R. tumjensis and later for R. purpurea, and complete fidelity of visitation by different pollinator species, bumblebees for R. tumjensis and a long‐tongued fly for R. purpurea. Furthermore, the nectar of R. tumjensis flowers is available to the shorter‐tongued bumblebees while R. purpurea nectar is less accessible, requiring deep probing from long‐tongued flies. Although flowering phenology is a strong current barrier that seemingly obviates any need for pollinator discrimination, this current pattern need not reflect selective forces occurring at the initial divergence of R. tumjensis. There has been considerable pollinator switching during the radiation of the Himalayan Roscoea, and the association of flowering time with type of pollinator in these sympatric species may have originated among the earliest or latest flowering individuals or populations of an ancestor in order to exploit either bumblebee activity early in the breeding season or long‐tongued fly abundance later in the season. These two sympatric Roscoea species add to accumulating evidence of the primacy of pre‐zygotic pollination traits in speciation among angiosperms even in the absence of post‐zygotic incompatibility. This article is protected by copyright. All rights reserved

ACS Style

Babu Ram Paudel; Martin Burd; Mani Shrestha; Adrian G. Dyer; Qing‐Jun Li. Reproductive isolation in alpine gingers: How do coexisting Roscoea ( R. purpurea and R. tumjensis ) conserve species integrity? Evolution 2018, 72, 1840 -1850.

AMA Style

Babu Ram Paudel, Martin Burd, Mani Shrestha, Adrian G. Dyer, Qing‐Jun Li. Reproductive isolation in alpine gingers: How do coexisting Roscoea ( R. purpurea and R. tumjensis ) conserve species integrity? Evolution. 2018; 72 (9):1840-1850.

Chicago/Turabian Style

Babu Ram Paudel; Martin Burd; Mani Shrestha; Adrian G. Dyer; Qing‐Jun Li. 2018. "Reproductive isolation in alpine gingers: How do coexisting Roscoea ( R. purpurea and R. tumjensis ) conserve species integrity?" Evolution 72, no. 9: 1840-1850.